isl_basic_{map,set}: explicitly store constraints defining div

[platform/upstream/isl.git] / isl_map.c

diff --git a/isl_map.c b/isl_map.c
index 2df3161..66cba37 100644 (file)
--- a/isl_map.c
+++ b/isl_map.c
@@ -590,8 +590,14 @@ static struct isl_basic_map *isl_basic_map_drop_div(struct isl_ctx *ctx,
        for (i = 0; i < bmap->n_eq; ++i)
                constraint_drop_vars(bmap->eq[i]+pos, 1, bmap->extra-div-1);
 
-       for (i = 0; i < bmap->n_ineq; ++i)
+       for (i = 0; i < bmap->n_ineq; ++i) {
+               if (!isl_int_is_zero(bmap->ineq[i][pos])) {
+                       isl_basic_map_drop_inequality(ctx, bmap, i);
+                       --i;
+                       continue;
+               }
                constraint_drop_vars(bmap->ineq[i]+pos, 1, bmap->extra-div-1);
+       }
 
        for (i = 0; i < bmap->n_div; ++i)
                constraint_drop_vars(bmap->div[i]+1+pos, 1, bmap->extra-div-1);
@@ -2209,6 +2215,14 @@ error:
        return NULL;
 }
 
+/* If the only constraints a div d=floor(f/m)
+ * appears in are its two defining constraints
+ *
+ *     f - m d >=0
+ *     -(f - (m - 1)) + m d >= 0
+ *
+ * then it can safely be removed.
+ */
 static int div_is_redundant(struct isl_ctx *ctx, struct isl_basic_map *bmap,
                                int div)
 {
@@ -2219,9 +2233,32 @@ static int div_is_redundant(struct isl_ctx *ctx, struct isl_basic_map *bmap,
                if (!isl_int_is_zero(bmap->eq[i][pos]))
                        return 0;
 
-       for (i = 0; i < bmap->n_ineq; ++i)
-               if (!isl_int_is_zero(bmap->ineq[i][pos]))
+       for (i = 0; i < bmap->n_ineq; ++i) {
+               if (isl_int_is_zero(bmap->ineq[i][pos]))
+                       continue;
+               if (isl_int_eq(bmap->ineq[i][pos], bmap->div[div][0])) {
+                       int neg;
+                       isl_int_sub(bmap->div[div][1],
+                                       bmap->div[div][1], bmap->div[div][0]);
+                       isl_int_add_ui(bmap->div[div][1], bmap->div[div][1], 1);
+                       neg = isl_seq_is_neg(bmap->ineq[i], bmap->div[div]+1, pos);
+                       isl_int_sub_ui(bmap->div[div][1], bmap->div[div][1], 1);
+                       isl_int_add(bmap->div[div][1],
+                                       bmap->div[div][1], bmap->div[div][0]);
+                       if (!neg)
+                               return 0;
+                       if (isl_seq_first_non_zero(bmap->ineq[i]+pos+1,
+                                                   bmap->n_div-div-1) != -1)
+                               return 0;
+               } else if (isl_int_abs_eq(bmap->ineq[i][pos], bmap->div[div][0])) {
+                       if (!isl_seq_eq(bmap->ineq[i], bmap->div[div]+1, pos))
+                               return 0;
+                       if (isl_seq_first_non_zero(bmap->ineq[i]+pos+1,
+                                                   bmap->n_div-div-1) != -1)
+                               return 0;
+               } else
                        return 0;
+       }
 
        for (i = 0; i < bmap->n_div; ++i)
                if (!isl_int_is_zero(bmap->div[i][1+pos]))
@@ -2549,6 +2586,37 @@ static int find_div(struct isl_basic_map *dst,
        return -1;
 }
 
+/* For a div d = floor(f/m), add the constraints
+ *
+ *             f - m d >= 0
+ *             -(f-(n-1)) + m d >= 0
+ *
+ * Note that the second constraint is the negation of
+ *
+ *             f - m d >= n
+ */
+static int add_div_constraints(struct isl_ctx *ctx,
+               struct isl_basic_map *bmap, unsigned div)
+{
+       int i, j;
+       unsigned div_pos = 1 + bmap->nparam + bmap->n_in + bmap->n_out + div;
+       unsigned total = bmap->nparam + bmap->n_in + bmap->n_out + bmap->n_div;
+
+       i = isl_basic_map_alloc_inequality(ctx, bmap);
+       if (i < 0)
+               return -1;
+       isl_seq_cpy(bmap->ineq[i], bmap->div[div]+1, 1+total);
+       isl_int_neg(bmap->ineq[i][div_pos], bmap->div[div][0]);
+
+       j = isl_basic_map_alloc_inequality(ctx, bmap);
+       if (j < 0)
+               return -1;
+       isl_seq_neg(bmap->ineq[j], bmap->ineq[i], 1 + total);
+       isl_int_add(bmap->ineq[j][0], bmap->ineq[j][0], bmap->ineq[j][div_pos]);
+       isl_int_sub_ui(bmap->ineq[j][0], bmap->ineq[j][0], 1);
+       return j;
+}
+
 struct isl_basic_map *isl_basic_map_align_divs(struct isl_ctx *ctx,
                struct isl_basic_map *dst, struct isl_basic_map *src)
 {
@@ -2560,7 +2628,7 @@ struct isl_basic_map *isl_basic_map_align_divs(struct isl_ctx *ctx,
 
        src = order_divs(ctx, src);
        dst = isl_basic_map_extend(ctx, dst, dst->nparam, dst->n_in,
-                       dst->n_out, src->n_div, 0, 0);
+                       dst->n_out, src->n_div, 0, 2 * src->n_div);
        if (!dst)
                return NULL;
        for (i = 0; i < src->n_div; ++i) {
@@ -2570,6 +2638,8 @@ struct isl_basic_map *isl_basic_map_align_divs(struct isl_ctx *ctx,
                        if (j < 0)
                                goto error;
                        isl_seq_cpy(dst->div[j], src->div[i], 1+1+total);
+                       if (add_div_constraints(ctx, dst, j) < 0)
+                               goto error;
                }
                if (j != i)
                        swap_div(dst, i, j);